Out for bugs

One immature male common yellow throat warbler working the ground, back and forth searching for bug bits. The mature male has a black mask. You can see the black cheeks beginning to grow in. This is a long yard. Two hours searching. He found food, but I couldn't see it.  This warbler is smaller than a sparrow.
 

I thought I found an egg,  kind of late for nesting season. It wasn't an egg. Parent birds don't stamp their eggs.